It appears on Higher Underbank House in Blackshaw, Calderdale, a yeoman clothier’s house built in around 1612 and might be some sort of weavers script, though there’s nothing online like it.

It’s been suggested that that it is a vernacular interpretation of the Greek words for Jesus Christ, though the person who sent in the photo is Greek and doesn’t recognise it, or that it stands for John Horsfall who had Higher Underbank built.

I think the second suggestion is more likely. The first letter might be a J, the second a funny kind of O and the third an N. I’m not sure about the symbol in the middle, but the next symbols might be an H and an F. So ‘Jon ? H f’ might be a personal script representing the name John Horsfall.

All could be possible… I think the second character and the one before last (from left of course) look similar.
if it is something from that time… we have to also to include, I guess, the possibility of hmm magical or superstitious practices associated with such shapes and inscriptions. Who knows, they might signify something related to protection or so.